High Water Temps While Towing Grades, Dealers keep offering same fix that doesn't fix

[GShail]

I thought I had this problem worked out but now it is back again. Here is a summary.



A few months ago I started to get fluctuating water temps that peaked to nearly 240 degrees. I couldn't hear my fan kicking in. I took the truck to the dealer, they did a resistance test and deemed the fan clutch bad and replaced it under warranty. There never was a code to indicate fan clutch failure.



Drove the truck another 12,000 miles and the problem returned. Took it to the dealer, they tested and replaced the fan clutch. Problem went away.



Drove the truck another 10,000 miles, the problem returned, took it to the dealership in Riverside, CA which was closest and they said "hey it's your fan clutch!" This time they replaced the fan clutch AND DID A TSB REFLASH. Problem went away.



Drove the truck this time about 3,000 miles and the symptom is back, spiking water temperatures, and AC is warm at idle.





Some things I have tried

1. Checked coolant which is at proper level and new.

2. Relocated the ground wire from my TST to inside the dash panel





This has to be more than bad fan clutches, I see another member is posting similar complaints.

 

[JHardwick]

Have you replaced the belt? That's a lot of fan to turn if the belt is going south!

 

[GShail]

Belt has maybe 50,000 miles on it, but I am going to take a closer look at it now that you mention it.

 

[Grey Wolf]

I was having the same problem with my '93 and picked up a new thermostat. After looking at it I could see were they made a change in the way the stat was constructed, anyway I installed it and the problem went away. I asked (Cummins) at the time if there were other stats for the newer years and was told they all use the same stat.

 

[Bob4x4]

I was having the same problem with my '93 and picked up a new thermostat. After looking at it I could see were they made a change in the way the stat was constructed, anyway I installed it and the problem went away. I asked (Cummins) at the time if there were other stats for the newer years and was told they all use the same stat.

There ara quite a few different t/stat part #'s and they are diferent from gen to gen.



Bob